Circuit interrupters



Oct. 30, 1956 A. R; CELLERINI CIRCUIT INTERRUPTERS Filed Feb. 2, 1953 2Sheets-Sheet l Oct. 30; 1956 I A. R. CELLERINI 2,769,066

CIRCUIT INTERRUPTERS Filed Feb. 2, 1953 2 sheets-sheet 2 `w|TNEs zlNvENToR /ff M Albert R. Cellerin.

United States Patent() CIRCUIT IN TERRUPTRS Albert R. Cellerini, Beaver,Pa., assiguor to Westinghouse Electric Corporation, East Pittsburgh,Pa., a corporation of Pennsylvania Application February 2, 1953, SerialNo. 334,551

14 Claims. (Cl. 200-147) This invention relates to circuit interruptersin general, and, more particularly, to arc-extinguishing structurestherefor.

The main object of my invention is to provide a more effective circuitinterrupter than has heretofore been manufactured; and also in additionto such eectiveness, I intend to provide such an improved circuitinterrupter of reduced dimensions.

A more specific object of my invention is to change the disposition ofthe metallic plate structure over that heretofore used in connectionwith circuit interrupters. In other words, heretofore it has been thecustom to dispose the spaced metallic plates substantially parallel tothe length of the circuit-breaker base. In my improved construction Idispose the spaced metallic plates substantially perpendicularly to thelongitudinal axis of the base. There occurs the advantage that theterminal structure of the breaker does not interfere with ready andfacilitated venting of the arc gases through the extinguisher.

Another object is to provide an improved arc-extingisher for a circuitinterrupter of the spaced-plate type.

Still a further object is to provide an improved arcextinguisher inwhich the arc is constantly kept in motion by preventing it fromsettling at the geometrical centers of the plates, thereby causing a hotspot to occur thereat.

Still a further object is to provide an improved spacedplate type ofarc-extinguisher in conjunction with a narlatch @11d 30 Which COOPYHCSWith row slot type of arc-extinguisher and improving the plate structureso that the consequent heating thereof during arc interruption will beminimized.

A further object of my invention is to provide an improvedspaced-metallic-plate type of arc-extinguisher in which an improved pairof arc-guide non-gas-evolving wa-ll members are utilized.

A further object of my invention is to provide an improved circuitinterrupter in which the active length of the spaced metallic plates maybe increased, yetA the length of the interrupter is reduced. This is ofparticular advantage since one form of circuit interrupter utilizing myinvention may be used in the walls of houses in which the studding widthis standard. Thus there is no advantage to reducing the height of theinterrupter, but there is a distinct advantage in reducing the lengththereof. This is obvious since the overall vertical mounting space isthus reduced.

Further objects and advantages will readily become apparent upon readingthe following specications, taken in connection with the drawings, inwhich:

Figure l is a vertical sectional view taken through a circuitinterrupter embodying my invention and shown in the closed-circuitposition;

Fig. 2 is a vertical sectional view taken along the line lI-II of Fig. llooking in the direction of the arrows;

Fig. 3 is a side elevational view of one of the shield plates utilizedin the construction depicted in Fi-g. l;

Fig. 4 is a side elevational view of one of the metallic plates utilizedin my improved arc-extinguisher;

to the outer end thereof and of the handle 18 to the ofi ICC Fig. 5 is avertical sectional view taken through a modied type of circuitinterrupter embodying my invention, the contact structure being shown inthe closed-circuit position;

Fig. 6 is a section-al View taken along the line VI-VI of Fig. 5 lookingin the direction of the arrows;

Fig. 7 is a top plan view of one of the insulating shield platesutilized in the arc-extinguisher of Figs. 5 and 6; and

Fig. 8 is a plan View of one of the magnetic plates utilized in thearc-extinguisher of Figs. 5 and 6.

Referring to the drawings, and more particularly to Fig. 1 thereof, thecircuit interrupter 1 comprises generally a base 2 and a cover 3 ofmolded insulating material, end terminals 4, 5, a stationary contact 6,a movable contact 7, and operating mechanism, generally designated bythe reference character 8. A current-responsive trip device 9 is alsoincluded, as is also an arc-extinguisher 10, the latter being providedto interrupt the arc drawn upon separation of the contacts 6 and 7.

The movable contact 7 is secured to a resilient contact arm 13, which,in turn, is secured by suitable means to a channel-shaped frame 14,pivotally supported by means of a pivot pin 15 on a U-shaped main frame16.

The operating mechanism 8 comprises a U-shaped operating lever 17 havingan operating handle 18 secured projecting through an opening 19 in thecover 3. The mechanism 8 also includes a cradle 21, a toggle comprisinga pair of toggle links 22, 23 and a pair of overcenter springs 24 (onlyone of which is shown). The operating lever 17 is pivotally mounted onpivot pins 25 supported in the sides of the frame 16, and the cradle 21is pivoted on a pin 26 also supported in the frame 16. One end of thetoggle link is pivotally connected to the cradle 21 by a pin 27, and thetoggle link 23 is pivotally connected to the f-ree end of thechannelshaped member 14 by means of a pin 28. The toggle links 22, 23are pivotally connected together by a knee pivot pin 29. The overcentersprings 24 are tensioned between the knee pin 29 of the toggle 22-23 andthe outer end of the operating lever 1'7. The cradle 21 is provided witha a bimetallic strip 31 adapted to releasably restrain the cradle 21 inthe position shown. The operating member 17 is provided with anextension 32 which is adapted to cooperate with the cradle 21 in orderto relatch the cradle 21 by manual movement position after the breakerhas been tripped open.

Under fault current conditions the bimetallic strip 31 will bend towardthe left, as viewed in Fig. 1, to release the cradle 21. The cradle 21will then be rotated in a clockwise direction by the overcenter springs24. During this rotation the line of action of the springs 24 changes tocause collapse of the toggle 22, 23 and opening of the contacts 6, 7.

Before the contacts may be closed, it is necessary to relatch the cradle21 with the latch member 31. This is effected by moving the operatinghandle 18 in a counterclockwise direction, during which movement the eX-tension 32 of the operating lever 17 engages and rotates the cradle 21in the same direction to re-engage bimetallic strip or latch 31. Thecontacts 6, 7 can now be closed by moving the handle 18 and theoperating lever 17 to the extreme right-hand position. This movementchanges the line of action of the overcenter springs 24 so as tostraighten the toggle 22, 23 and thus effect closing of the contacts 6,7.

The breaker may be opened manually by moving the handle 18 toward theleft. During this movement the line of action of the overcenter springs24 is moved to the left of the pivot pin 27, causing the springs toexert a force on the knee of the toggle 22-23 in a direction to causecollapse of the toggle, which results in movement of the movable contact7 to the open position. The contacts 6, 7 are closed in the previouslydescribed manner.

My invention'is particularly concerned with the arcextinguisher 1t),which is utilized to interrupt the arc drawn between the contacts 6, '7during the opening operation of the interrupter. The extinguisherlrcomprises a plurality of spaced non-magnetic metallic plates 33, theconguration of which is more clearly shown in Fig. 4 of the drawings.

With reference to this `ligure it will be observed that eachnon-magnetic plate 33 has aslot 34 formed therein and a pair'of legportions 35. A pair of shield Vplates 37, preferably formed of liber orother gaslevolving material are disposed on opposite sides of the'plates 33. In certain instances it may, however, be desirable to formthe shield plates 37 -of a suitable non-gas-evolving insulatingmaterial, such as asbestos.

Associated with the stationary'contact 6 is an arichorn or arc-'runner44, with which the end metallicplate 33A makes contact, as shown inFig. 1. Essentially therefore the end plate 33A forms an extension orright angle bend `of the arc-'runner 44, so that when the movablecontact has moved to the open position, as indicated by the`dotted-lines 45, the established arc 46 will rapidly move successivelythrough the positions 47, 4S to the position 49, in which it cissubstantially parallel to the longitudinal V`axis of the base 2. The arc49 moves into the apex 41 of each plate 33 and hence onto the plates 33where the arc 49 is subdivided into a plurality Vof serially-relatedarc-portions, designated bythe reference character v51 in Fig. 1. i

To assist in the upward travel of the arc 46, I preferably provide ablowout coil 53, which is serially connected in the circuit as shown inFig. l. The blowout coil 53 has one end 54 connected with the terminal'5 and has the other end 55 connected with the stationary contact 6, as'shown in Fig. l. Consequently, in the closed-circuit position of theinterrupter, as indicated in Fig. l, the electrical circuit passes fromthe left-hand terminal 4 through the strip 56, through the bimetallicstrip `31 and through the exible connector 57 to the movable contact 7.The circuit extends from the stationary contact 6 throughthe connection55 and through the blowout coil 53, by way 'of the connection 54, toTthe right-hand terminal of the interrupter. It will, therefore, beunderstood that the blowout coil 53, being in series circuit at alltimes, will constantly be energized and will Yset `up va magnetic tluXthrough the core 58, spaced by an insulating tube 59 from the blowoutcoil 53, and through a pair of magnetic pole plates 60 disposed onopposite sides of the extinguisher 10. v

Supporting the spaced metallic plates 33 in a fixed spaced relation area pair of slotted insulating support plates 61, more clearly shown inFigs. 2 and 3 of the drawings. With Vreference vto Fig. 3 it will benotedv that each insulating support plate 61 has a plurality of slots62, into which tit the plates 33, the olfset or shoulder portions 63 ofthe plates 33 coming to rest at the bottoms of the slots '62 of theplates 61. Thus'I have constructed an arc-chute employing slottedmetallic plates 33, and have 'included the added feature of connnilg thearc 47-49 into as narrow a slot 64 as desire It is a well-known factthat either'of the above means is employed singly in circuit breakers.Both of these means of extinguishing an arc, however, have not beensuccessfully combined heretofore. This is due to the fact that a narrowslot 64 has generally been thought to require that the metallic platealso be narrow to tit into l the slot. The result has been that notenough metal is present to dissipate vthe heat generated by the arc,and, therefore, in the 'past the'plates have been destroyflt In myimproved arc-extinguisher 10, means are provided by which 'the arc canbe confined into a narrow slot while at the same time a wide metal plate33 may be used.

The slotted supporting plate 61 is preferably formed of an insulatingmaterial such as asbestos board or porcelain and having the slots 62 asshown. When two of these plates are placed side by side the adjacentslots 62 form a means by which the metal plates 33 may be inserted atthe back so that a 'stack of plates 33 is 'formed to subdivide theYestablished arc. The plates 33 .are supported in the substantiallyparallel slots '62, as shown in Fig. 1 -of the drawings. As indicated inFig. 4, the plates 33 'have the usual slots 34 and function in thecustomary manner of Vsubdividing the initially established arc. Thesubdividing function of the plates 33 is not impaired at all by theabove method of supporting them.

The breaker contacts 6, 7 are located between the lower ends of the twoAceramic plates 61 so that vthe initially established arc 46 will bedrawn into the slot 64 between the two ceramic plates V61. The arc, aulater position Aof which is indicated by the reference numeral 49, can,therefore, be confined and deionized in a slot 64 having "the width ofthe distance between the support plates 61.

It will be observed that each plate 33 has an area greater than the areaof the slot 64 and, although the arc 49 'cornes in direct contact with'the plates 33 only at 'the area 6'4, yet the heat therefrom will bedispersed immediately over the total plate area including not only thatbetween plates V61, but also the areas 65, 66 outside of the supportplates 61. The arrangement, therefore,

will squeeze 'the arc '49 within area 64, but still will permit the'useof a wide plate 33 for good heat dissipation.

It will be observed that the magnetic flux passing between l'the 'pole"plates 60, as indicated bythe arrows V63 in Fig. 2, will assistinupward movement of the arc 49.'

An insulating lplate 69 protects the blowout coil l53 from thearc '46,`and the shield plates 37 protect the pole plates from the arcs Y51 nearthe top of the extinguisher10.

From the foregoing description it will be apparent that I havechangedthe location or disposition of the spaced metallic plates 'inthecircuit breaker, with respect lto the constructionwhich/has previouslybeen used in this type of breaker.` As well known by those skilled inthe art, previously'the metallic plates were disposed substantiallyhorizontally, or parallel to the longitudinal Yaxis of the base 2.VIn'the construction disclosed herein the plates not only may be longerthan these heretofore used Vbecause Yof A their 'particular location,but also lthe terminal structu'reS does 'not impair venting as was thecase in the prior art interrupters of thistype. Moreover, the circuitinterrupter `as `a whole is Vshorter in a lengthwise direction since nospace needbe provided for the plates 33 between the terminal structure 5and the contacts 6, 7 as was the case heretofore.

In addition, when the breaker is constructed as above, 'the vent 72 inthe cover 3, which may be provided wtih a'suitable cooling screen 73, isdisposed Moreover, an exgases between the rnet'al plates 33. Thisexpansion space 74 is, of course, readily vented by the immediatelyadjacently disposed screened vent 72. I

The above construction rapidly moves the arc 46 away from both contacts6, 7 immediately after opening of said contacts and keeps the arc movingand stretching in a manner which lis not possible with conventionalbreakers of -vthis type,

arc gases is -at a point sufliciently far away from the con-v The'iinallocation of the Aarcs 51 and the tets 6, 7 to prevent contamination ofthe Contact area by these gases. Since the plates 33 may be longer thanin conventional nterrupters of this type, the plates willcorrespondingly have more area with the result that cooling action isincreased, and also the arcs 51 can be kept in motion longer than ispossible in a shorter conventional circuit interrupter. In addition, theV-shaped slot can be made longer and shallower so that the splitting upof the arc 49 is facilitated. Especially important is the fact that withthis arc chute 16 it is open at the top leading into the expansionchamber 74, so that the arc motion will be positive and unobstructed.

' The general manner of operation will be obvious from the foregoingdescription. Briefly, in recapitulation, the separation of the contacts6, 7 will cause the initially established arc 46 to expand upwardly andoutwardly to the successive positions 47 and 48, the lower terminalthereof, running rapidly outwardly along the arc runner 44, shieldedfrom the blowout coil 53 by the insulating plate 69. The arc nallyassumes a configuration substantially parallel to the longitudinal axisof the base 2, Wherein it is substantially horizontal assuming theinterrupter to be maintained in the position shown in Fig. 1.

The magnetic eld between the pole plates 60, as indicated by the arrows68 in Fig. 2, moves the arc between the closely-spaced insulatingsupports 61 and through the apices of the plates 33 and thereonto. Notonly are the terminals ends of the arc portions 51 cooled by the platestructure itself, but also the intervening arc portions 51 are cooled bythe immediately adjacently disposed insulating support plates 61,because of the restricted space 64 therebetween. The arcs continue tomove upwardly until they are cooled and extinguished.

Preferably the non-magnetic plates 33 are formed of a nickel-chromiumalloy, as set out and claimed in my co-pending application led February16, 1950, Serial No. 144,461, now Patent No. 2,687,462, issued August24, 1954, and assigned to the assignee of the instant applica- Ition.The support plates 61 and the side shield plates 37 may either be formedof a non-gas-evolving insulating :material such as asbestos, or of asuitable gas-evolving ma-terial, such as fiber or boric acid dependingupon the current and voltage interrupting requirements, as well `knownby those skilled in the art.

In the embodiment of my invention disclosed in Figs. .'5-8 the operatingmechanism 8 and the trip device 9 are .the same as heretofore disclosedin connection with the interrupter of Figs. 1-4, and, consequently, theywill not be further discussed. In this embodiment of my invention, theblowout coil 58 heretofore described in connection with Fig. l isomitted, and the metallic plates 7S are formed of a suitable magneticmaterial, such as iron or the like. The modified type ofarc-extinguisher 76 may be used with ceramic supports 77, theconfiguration of which is more apparent from an inspection of Figs. 6and 7. These supports 77 serve two purposes. One purpose is to supportthe plates 75 and the other purpose is to serve as arc shields.Referring to Fig. 7 it will be noted that the ceramic support plates 77are provided with full grooves or slots 79 on one side and short grooves80 on the other. This results in the provision of a plurality of pairsof spacing members 90 (Fig. 7) integrally formed with the supports 77.Thus a spacing member 90 of one support 77 cooperates with a spacingmember 90 of the other support 77 to constitute a pair of spacingmembers. The plates 75 are provided with legs 81, the inner sides 82 ofwhich tit into the outer slots 79 of the cooperating support plates 77,as more clearly shown in Fig. 6 of the drawings. It will be noted thatthe central portion 83 of the plates 75 extend downwardly to form anapex 41. The plates 75 are slipped into the grooves 79, 80 from theback, and following assembly bolts 84 are provided to hold the plates 75and the two support plates 77 together, as shown more clearly in Fig. 6.

. This type of construction may also be used for interrupting largeamperage currents since it will be noted that a considerable portion ofthe legs 81 of the plate 75 is external to the support plates 77 andhence is available for transmission and dissipation of heat to theambient space during arc interruption. The design permits very electivecooling and exhaustion of the hot gases to the outer end of theextinguisher 76. At the same time the arc 49 can be drawn betweennon-gas-forming cool ceramic walls. The walls of the spaced supports 77are tapered to form a tapered entrance portion or entering arc passageS5 with a small throat for apices 41 in thev metal plates 75.

This groove 85 forces the arc 49 to reduce in crosssection as themagnetic field forces it back into the throat 41, thereby increasing thearc resistance and the rate of arc cooling. This squeezing of the arc 49makes its path outside the plates 75 unstable; therefore, the arc 49readily splits up and enters the plates 75 as the arc portions 51. Thisaction takes place in conventional spaced slotted metallic platestructures where no shields 77 are used, but the trouble has been thatthe arc 49 may resist being squeezed into the throat 41 and may hang onto the legs of such slotted plates of prior art arc chutes.

The magnetic field is set up as indicated by the arrows 86 of Fig. 8 andacts on the arc 49 as in ordinary are chutes. However, with my improvedconstruction involving the wide plates 75, the plates will not heat upas much as in prior art arc chutes because the wide plate area canabsorb the heat without overheating too much.

Referring to Fig. 8, it will be observed that there are provided locksor tabs 36 to secure the outer sides of the plates 75 to a pair ofinsulating side plates 87. Also each metallic plate 75 is provided withan aperture 39, which align in the assembled state, as viewed in Figs. 5and 6, to support a gas-evolving rod 40, which passes substantiallythrough the geometric centers of the plates 75. In addition, disposedbetween aperture 39 and the apex 41 of each plate 75 is a smalleraperture 42, the function of which will be more apparent hereinafter.

When an arc moves to the apices 41 of the plates 75 and enters the solidparts of the plates 75, it will move back to the geometric center of thesolid section of the plates 75 and then settle there because themagnetic forces acting on the arc are at equilibrium at that point.Unless the arc 51 goes out very quickly, therefore, the plates will beburned at that point.

It is an additional purpose of my invention, in the construction shownin Figs. 5 and 6, to provide a means of keeping the arcs 51 in motionuntil they are extinguished by the plates 75 so that no hot spots occurin the plates 75.

As previously mentioned in connection with Fig. 8, each metallic plate75 has two holes 39, 42 provided in them in line with the normal travelof the arcs 51. The small hole 42 is left open, but the large hole has afiber rod 40 extending through the plates 75 so that it forms a solidiber column in the direct path of the arc. As the arc 51 moves upwardlyaway from the apex 41 of the plate 75 it tirst meets the small hole 42in its direct path. This hole 42 then deflects the arc 51 to the left orright, as viewed in Fig. 6, so that the arc 51 strikes the fiber rod 40sideways as indicated by the arrow 71. The heat from the arc 51 will nowgenerate a small amount of iber gas from the rod 40 and this gas willshoot out through the arc body 51 and therefore cause the arc to moveslantwise away from the fiber column 40. When the arc has moved out ofthe vicinity of the liber, no more gas will be generated and thereforethe arc 51 will come to rest. At this point, the arc 51 is not at thegeometric centers of the plates any more; therefore, the inherentmagnetic forces will come into play and force the arc 51 towards theliber column 4i) again. This action can repeat indefinitely until thearc is extinguished.

. It can be seen, therefore, that in this way the arc 51 can be keptconstantly in motion all the time of its duration, thereby preventingoverheating of the plates 75 in spots with its resultant deleteriouseiects. on. are extinctionand dat'rage to` the plates..

The manner of are extinction is generally similar to that heretoforedescribed in connection with Figs. l` and 2. The arc 49 is moved rapidlyupwardly by the distorted magnetic iield thereabout as caused by thepresence of the several spaced magnetic plates 7S. It moves quicklyupwardly or outwardly between the inner walls of the non-gas-evolvingsupport plates 77 until it reaches the apices 4l, where it enters theplates 75 as subdivided arcs 51. The arcs 51 are deilected by the holes42 into angular contact with the gas-evolving liber rod 4d, the latterbeing disposed substantially at the geometric centers of the plates '75;The arcs 51 will constantly move or vibrate between the rod 4@ and theimmediately adjacent-ly disposed areas of the plates 75 by two coniicting forces. One force, of course, will be the forcey exerted by thegas evolved atth'e rod 40 by the heat of the arcs 51; The other opposingforce will be the inherent magnetic tendency for the arcs 51 to becomestabilized at the geometric centers of the plates 75. The net result israpid movement of the arcs 51 to decrease any localized heating of theplates 75 to rapidly bring about arc extinction.

While this process is going on there occurs a rapid flow of gasoutwardly between the plates 75 into the expansion space 74. Arcextinction soon results.

From the foregoing description of two different ernbodirnents of myinvention, it will be apparent that I have shortened the length of thebreakers l, 89 by placing the plates 33, 75 substantiallyperpendicularly to the base 2. and by swinging the initially establishedarc 46 around from an initial position substantially perpendicular tothe base 2 to an ultimate position where it is substantially parallel tothe base 2. The plates 33, 75 may be longer than in conventionalstructures even though the interrupter l, 89 is shorter, considered as awhole. Rapid gas ow occurs through the spaced plate structure and intothe expansion space '74, where it is rapidly vented out of the breakerthrough the vent 72 and at a location away from the terminal structure5.

Although I have shown and described speciiic structures, it is to beclearly understood that the same were merely for the purpose ofillustration, and that changes and modifications may readily be madetherein by those skilled in the art without departing from the spiritand scope of the invention.

I claim as my invention:

l..l A circuit interrupter including a base, contact means forestablishing an ,arc initially substantially perpendicularly to thebase, means for subsequently swinging the arc around in a planesubstantially perpendicular to the base so that the arc is substantiallyparallel to the base, a plurality of spaced metallic plates disposedsubstantially .perpendicularly to said base, and means includingsaidspaced metallicl plates for extinguishing the arc.V

2. A circuit breaker including an insulating base, a stationary contactmounted on said base, a movable contact separable away from thestationary contact to establish an :arc initially substantiallyperpendicularly to the base, means including an arc runner forsubsequently swinging the arc around in a plane substantiallyperpendicular to the base to a position that is substantially parallelto the base, a plurality of spaced metallic plates disposedsubstantially perpendicularly to the base, and the arc moving onto themetallic plates to be subdivided thereby to effect the extinctionthereof.

3. A circuit interrupter including enclosing means, a base and a coverdefining said enclosing means, the cover having a vent opening, contactmeans disposed interiorly of the enclosing means and separable toestablish an arc initially substantially perpendicularly to the base,means for swinging said arc -around in a plane substantiallyperpendicular to said base so that it is substantially parallel to thebase, and a plurality of spaced metallic plates disposed substantiallyperpendicularly to the base for extin'guishing the arc;

4. circuit interrupter including means for establishing an arc, meansincluding a plurality of spaced magneticl conducting plates toextinguish said arc, the arc being subdividedbly the conducting platesinto a plurality of serially related a'rc portions, each of a pluralityof said plates having. a relatively small opening therethrough adjacentthe geometric center of the plate, and gas-evolving means extendingthrough a plurality of such openings to assist in extinction of the arc.

5. A circuit interrupter including means for establishing -an arc, meansincluding a plurality of spaced magnetic plates to extinguish said arc,each of a plurality of said plates having'. an opening therethroughadjacent the geometric. center of the plate, and a gas-evolving rodextending through a plurality lof such openings to assist in extinction'of. the arc'.

6. A circuit interrupter including. separable contact means forestablishing an arc, a pluralityV of spaced, slotted, magneticconducting plates for subdvidingl the established arc, each such platehaving an arc receiving edge, a pair of cooperating, insulating,tapered, arcguiding shield support members, said shield support membershaving slots therein for supporting said magnetic plates in spacedrelation, the pair of tapered shield support members forming a taperedentrance portion for progressively constricting the arc and forcing itto enter through the slots of the plates and onto the plates to besubdivided thereby, and the leg portions of the slotted plates beingdisposed exteriorly of the shield support members for cooling to theambient space.

7. A circuit interrupter including separable contact means forestablishing an arc, a plurality of spaced, slotted, magnetic conductingplates for subdividing the established arc,l each such plate having anedge for split.- ting up the arc, a pair of cooperating, insulating,tapered, arc-guiding shield support members, said shield support membershaving slots therein for supporting said magnetic plates in spacedrelation, the pair of tapered shield support members forming a taperedentrance portion for progressively constricting the arc and forcing itto enter onto the plates, the shield support members extending anappreciable distance in substantially parallel spaced relation in thedirection ofarc movement beyond said plate edges, and the leg portionsof the slotted plates being disposed exteriorly of the shield supportmembers for cooling to the ambient space.

8. A circuit interrupter including means for establishing an arc, spacedconducting magnetic plates for extinguishing the arc and between whichthe Iarc may be subdivided, a plurality of pairs of insulating spacingmembers for spacing the plates apart, the pairs of spacing membersdefining arcing spaces confining the movement of the arc onto theplates, and at least some of the magnetic plates having heat-dissipatingportions outside of the arcing spaces and exteriorly -of the spacingmembers to take advantage of the cooling eiiect of the ambient space.

9. A circuit interrupter including means for establishing an arc, spacedU-shaped conducting magnetic plates for extinguishing the arc andbetween which the arc may be subdivided, a plurality of pairs ofinsulating spacing members for spacing the plates apart, the pairs ofspacing members defining arcing spaces confining the movement of the arconto the plates, and at least some of the magnetic plates havingheat-dissipating portions outside of the arcing spaces and exteriorly ofthe spacing members to take advantage of the cooling eiiect of theambient space.

l0. A circuit interrupter including means for establishing an arc,spaced U-shaped magnetic conducting plates for extinguishing the arc, apair of spaced supports deiining a tapered entrance portion for the arcIand having associated therewith a plurality of pairs of insulatingspacing members for spacing the plates apart, the pairs of spacingmembers defining -arcing spaces confining the movement of the arc ontothe plates, and at least some of the magnetic plates havingheat-dissipating portions outside of the arcing spaces and exteriorly ofthe supports to take advantage of the cooling effect of the ambientspace.

11. A circuit interrupter including a housing having a base portion, thehousing having an opening opposite the base portion, an operatingmechanism, a handle for actuating the operating mechanism projec 'ngthrough said opening in the housing, a relatively stationary contactmounted on the base portion and having an arc horn which initiallyextends substantially parallel to the base portion and then makessubstantially a right angle bend toward the side of the housing throughwhich the handle projects, a movable Contact cooperable with therelatively stationary contact to establish an arc, and one terminal `ofthe arc moving out along the arc horn to a position so that the larc issubstantially parallel to the base portion.

12. A circuit interrupter including a housing having a base, the housinghaving an opening, an operating mechanism, a handle for actuating theoperating mechanism projecting through said opening in the housing, arelatively stationary contact mounted on the base and having an arc hornwhich initially extends substantially parallel to the base portion andthen makes substantially a right angle bend toward the side of thehousing through which the handle projects, a movable contact cooperablewith the relatively stationary contact to establish an arc, a pluralityof spaced plates disposed substantially perpendicularly to the base forextinguishing the arc, and one terminal of the arc moving out along the-arc horn to a position so that the arc is substantially parallel to thebase.

13. The combination in a circuit interrupter of a base, a cover for thebase having an opening, an operating mechanism, a handle for actuatingthe operating mechanism projecting through the opening, contact meansincluding a relatively stationary contact and a movable contact forestablishing an arc, the relatively stationary contact having an arcrunner which initi-ally extends substantially parallel to the baseportion and then makes a right angle bend toward the cover, the contactmeans establishing yan arc, one terminal of which runs along the arcrunner to a position so that the arc is substantially parallel to thebase, and means for extinguishing arc.

14. The combination in a circuit interrupter of a base, Ia cover for thebase having an opening, an operating mechanism, a handle for actuatingthe operating mechanism projecting through the opening, contact meansinc nding a relatively stationary contact and a movable contact forestablishing an arc, the relatively stationary contact having an arcrunner which initially extends substantially parallel to the baseportion and then makes a right angle bend toward the cover, the contactmeans establishing an arc, one terminal of which runs along the arcrunner to a position so that the arc is substantially parallel to thebase, and means for extinguishing the arc including a plurality ofspaced plates disposed substantially perpendicularly to the base.

References Cited in the ile of this patent UNITED STATES PATENTS1,868,442 Corbett July 19, 1932 2,065,357 Von Hoorn Dec. 22, 19362,116,791 Jackson May 10, 1938 2,174,232 Baker Sept. 26, 1939 2,240,623Lindstrom May 6, 1941 2,564,178 Strobel Aug. 14, 1951 2,575,730 Sandinet al. Nov. 20, 1951 2,633,518 Miller Mar. 31, 1953

